Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Use Collider
COLLIDER_USE
Parameter: Bounce
COLLIDER_BOUNCE
Parameter: Friction
COLLIDER_FRICTION
Parameter: Stick
COLLIDER_STICKINESS
Parameter: Collider Side
CLOTH_PBD_COLLIDER_SIDE
Parameter: Set
COLLIDER_SET_EXCL
Parameter: Clear
COLLIDER_CLEAR_EXCL
Parameter: Show
COLLIDER_SHOW_EXCL
Parameter: Draw
COLLIDER_DRAW_EXCL